In the 1960s, while Earth’s gravity maps were being charted, it was discovered that the Hudson Bay region had less gravity than anywhere else on Earth. Now, the difference is slight, about one part in 25,000, but no one understands why.

Why does Hudson Bay have less gravity?

NASA/Goddard Space Flight Center Scientific Visualization Studio

Gravity isn’t uniform around Earth. Our planet bulges somewhat. But gravity is proportional to mass. The larger an object, the more pull it has. But for the Hudson’s Bay area, this wasn’t the case.

Recent studies have suggested that it could be that the mantle rocks beneath are falling downward. Another theory suggests that during the Ice Age, about 20,000 years ago, the glaciers pushed down on the crust and it hasn’t come back up yet.

4. 95 per cent of our oceans remain unexplored

While space is considered the “final frontier” for many, there is a much closer region of our solar system that remains unexplored: our oceans.

About 95 per cent of the ocean hasn’t been explored, with about 99 per cent of the ocean floor remaining a mystery to us.

Changes in global climate will greatly affect aquatic life, particularly in the tropics.

Keoki Stender, Marinelifephotography.com

The problem is two-fold: for one, our oceans are vast, accounting for more than 70 per cent of our planet. Another is that accessing regions is difficult for us: we weren’t built to live under water, so tools and technology are needed to assist us.

5. There are about 8.7 million species on Earth

In 2011, a study estimated that there are about 8.7 million species on our planet — including animals, plants, fungi and protozoa — with 6.5 million on land and 2.2 million in our oceans.

But that amazing part is that we know a fraction of them.

A Malayan pangolin is seen out of its cage after being confiscated by the Department of Wildlife and Natural Parks in Kuala Lumpur.

JIMIN LAI/AFP/Getty Images

The study found that 86 per cent of species on land and 91 per cent in oceans have yet to be discovered.

So how could the researchers calculate the number of species on Earth if most of them are unknown? They used 253 years of taxonomy. Essentially, they took the number of species catalogued to date (about 1.25 million) and analyzed numerical patterns within the classification system. And of course, there is a margin of error of about 1.3 million.

Either way, our planet — the only one in our solar system we know of that holds life — is a vibrant, complex system teeming with life. We need to take care of it.